Refrigerator



June 24, 1941. w. R. HAlNswoRTH REFRIGERATOR Filed DSC. l, 1938 1NVENTOR.

QLQGMZ.

ATTORNEY.

Patented June 24, 1941 REFRIGERATOR William R. Hainsworth, Larchmont, N. Y., assignor to Servel, Inc., New York, N. Y., a corporation of Delaware Application December 1', 1938, Serial No. 243,340

1 Claim.

My invention relates to food preservation by the combined effects of refrigeration and light, and it is an object of the invention to carry out such food preservation in a refrigerator by an improved method and apparatus as will appear from the following description in connection with the accompanying drawing, in which Fig. l is a the greatest bacteria killing effect without production of ozone.

An ultra-violet light source placed in a refrigerator storage compartment also emits heat sectional part view of a refrigerator embodying p the invention, and Figs. 2, 3, and 4 are views showing a part in Fig. 1 in different positions of operation.

Referring to Fig. 1, a refrigerator I0 provides a thermally insulated food storage compartment I I accessible by means of a door I2. An evaporator or cooling element 21 of a refrigeration ap# paratus unit is located in the upper back part of compartment II for cooling air in the compartment. On the ceiling of the storage compartment II is a lamp I3. This lamp is of a type which emits rays of short wave length, referred to as ultra-violet rays.

Low Vtemperatures produced by refrigeration inhibit propagation of food` spoiling bacteria. There is probably no killing effect. Short ultraviolet rays kill bacteria but apparently do not inhibit propagation. In order to preserve food by ultra-violet light alone, it would be necessary to kill bacteria by light rays and the bacteria propagation rate is great at high atmospheric temperatures. Food preservation is carried out by refrigeration alone for limited lengths of time because proper cooling inhibits bacteria propagation. Preservation of food by refrigeration could be carried out for longer periods if there were fewer bacteria present. Also, preservation of food can be carried out at higher temperatures if the greater bacteria propagation rate is balanced by killing of bacteria. It is thus advantageous to combine the effects of proper ultraviolet raysy and refrigeration in the preservation of food.

Short light rays are usually measured in ngstrm units, one unit being 10- centimeter. The shorter rays have a greater killing effect, meaning that the shorter raysv kill a greater number of bacteria in a given length of time or the same number of bacteria in a shorter length of time.

However, shorter rays in air produce ozone which is detrimental to food preservation on account of its odor and effect on food flavor. Rays shorter than about 2400 ngstrm units produce too much ozone. The ultra-violet ray source I3 should therefore provide a preponderance of rays in the neighborhood of 2500 ngstrm units to obtain which places an extra load on the refrigeration apparatus which may negative the beneficial result of the addition of the light source. I therefore provide in a refrigerator storage compartment a source of ultra-violet light which operates only part of the time that the refrigerator is in use and automatically correlates the operation of the light source with the use of the refrigerator as indicated, for instance, by opening and closing of the door.

The lamp I3 in the ceiling I5 is connected to an electric current supply line 29 through a switch I4 arranged to be operated by opening and closing of the refrigerator door I2. Switch I4 includes a spring strip I1 having a contact I8, a contact member 20, and a bimetal element or strip 2| having a double contact 22. The strips I'l and 2| are mounted at one end on an insulating block 23. The bimetalI thermostatic strip 2l is located below the strip I'l, and the double contact 22 arranged to engage both contacts I8 and 20 upon exure of the strips.

A heating element 24 is arranged in heating relation to the thermostatic strip 2l and is connected to the line 29 only when all of the contacts I8, 20 and 22 are engaged.

Spring strip I1 is arranged so that its contact I8 bears against contact 22 and causes contact 22 to bear against contact 20, as shown in Fig. 3. When the refrigerator door is openedl the switch operating member 25 is in the position shown in Fig. 3. The heater 24 and lamp I3 are both connected in circuit. The bimetal strip 2I becomes heated and tends to flex upward.

When the door I 2 is closed, the switch operating member 25 moves strip Il upward. The bimetallic strip 2I also moves upward so that contacts I8 and 22 remain engaged while contacts 20 and 22 become disengaged. The lamp I3 continues to burn but the heater 24 is turned off. This is shown in Fig. 4.

If the door I2 is not again opened to start the heater 24, the bimetal strip 2I `cools until it moves downward' and disengages contacts I8 and 22, as shown in Fig. 2, to open the circuit of the lamp I3.

The lamp I3 continues in operation as long as door I2 is opened at intervals less than the cooling interval of the bimetal strip 2l. I'he switch operation may be made to have snap accessible by means of a door, refrigeration ap-l paratus for cooling air in said compartment, a 10 source of ultra-violet light for irradiating food or the like ln said compartment', a switch operated by movement of said door for controlling said' light source, and means for delaying opening of said switch after closing of the door comprising a thermostatic element and an electric heater for the element connected to be turned on and off upon opening and closing of the door.

WILLIAMV R. HAINsWoRTH. 

